Fluid floated belt for suction boxes



April 25, 196] E. J. JUSTUS 2,981,329

FLUID FLOATED BELT FOR SUCTION BOXES Filed Nov. 5, 1958 /0 E 1 b 1 /5 (E9) 0 {4 WHIWW" IW'W 2 Sheets-Sheet l ha 21hr 509612" c[ cfus fus April1961 E. J. JUSTUS 2,981,329

FLUID FLOATED BELT FOR SUCTION BOXES Filed Nov. 3, 1958 Egw 2Sheets-Sheet 2 Edgar cf r/usfus Z: 7 741; Z'Q/ Q'QQZ Z E FLUID FLOATEDBELT FOR SUCTION BOXES Edgar J. Justus, Beloit, Wis., assignor to BeloitIron Works, Beloit, Wis., a corporation of Wisconsin Filed Nov. 3, 1958,Ser. N 771,546

Claims. (Cl. 162--367) The present invention relates broadly to papermachines, and is more particularly concerned with new and improved meanshaving especial utility in the support of the moving belt traveling incontact with the forming wire and suction box in the Fourdrinier typepaper machine.

As is well known, the conventional Fourdrinier type paper machinecomprises a looped traveling forming wire presenting a forming reachextending from a breast roll, at which the stock is flowing onto thewire, to a suction couch roll located approximately at the station atwhich the formed web is removed from the wire. Various dewateringdevices are mounted beneath this reach of the forming wire, and one ofthe more common dewatering devices is known as a suction box andpresents a flat perforate top to the bottom side of the wire. Theinterior of the suction box is exhausted to assist in drawing water fromthe web through the wire and through the perforations in the fiat top ofthe suction box. The pressure dififerential which is thereby createdtends to hold the traveling wire down against the stationary flat top ofthe suction box so as to increase wear on the wire.

Various devices have been suggested for the purpose of avoiding wirewear caused by drawing the moving wire over fixed suction boxes, and oneof the most well known of these devices is often referred to as theEvans Roto Belt, which is described and claimed in US. Patent No.2,039,308, issued to William P. Evans on May 5, 1936. In the Evansstructure a perforated moving belt with solid edges is installed betweenthe traveling Fourdrinier wire and the suction box covers in an attemptto reduce wire wear and also wear on the suction box covers. Theconventional manner of driving the moving belt is by means of two mainrolls which form the loop of the belt. Numerous difiiculties arise fromthe use of the driven rolls, and one serious problem presented ismaintaining the rolls properly balanced with respect to each other sothat the moving belt is at all times tensioned to the proper degree.Thus, if either of the rolls is not properly centered with respect to apredetermined point, or one roll driven at a greater speed than theother, smooth and efficient operation of the paper machine cannot beobtained. Second, the two main rolls add substantially to'theinstallation and operating costs of the paper machine.

The instant invention resides in a novel, simple and particularlyefiective arrangement for overcoming these difficulties. In accordancewith the present teachings, the moving belt is supported at oppositeends of the suction box by an arcuately shaped lubricated memberextending essentially entirely across the full width of the belt andprovided with a transverse lubricating groove in preferably the oncomingface thereof. Each member or shoe as constructed in accordance with theprinciples of this invention is lubricated with water, and the grooveformed therein has a generally rounded U-shaped crosssection with anoutwardly flared rounded discharge lip so that the water can flowuniformly out of the groove over the lip to provide a lubricating filmon the surface of the shoe under the belt. One manner of assuringuniform distribution of the lubricating water along the length of thegroove is to employ a header pipe having a series of stems connected tothe bottom of the groove at spaced intervals along the length thereof.

It is accordingly an important aim of the present invention. to providean improved paper machine, and more particularly, to provide novel meansfor supporting the moving belt traveling over a suction box in aFourdrinier type paper machine.

Another object of this invention lies in the provision of lubricatedmembers positioned at the oncoming and ofirunning sides of a suction boxwhich eflectively support the moving belt, reduce the wear thereon, sealthe belt-suction box interface against the entry of air, and which maybe readily fabricated, installed and removed.

Other objects and advantages of the invention will be come apparentduring the course of the following description, particularly when takenin connection with the accompanying drawings.

In the drawings: a

Figure 1 is an essentially diagrammatic elevational view of a papermachine embodying belt support means constructed in accordance with theprinciples of this invention;

Figure 2 is an enlarged view of a preferred form of suction box andfurther showing the lubricated belt sup port means of this invention;

Figure 3 is an enlarged sectional fragmentary detail view takensubstantially along the line III-III of Figure 2, with parts showndiagrammatically;

Figure 4 is a detail view of a portion of one lubricating belt supportmember, showing the groove construction therein and one form of waterinlet which may be employed;

Figure 5 is a sectional view taken substantially along the line VV ofFigure 4; and

Figure 6 is a fragmentary detail top plan view. of a suction box coverwhich may be utilized in connection with the present invention.

Referring now to the drawings, there is shown in Figures 1 and 2 a papermachine indicated generally by the reference numeral 10, and comprisinga looped forming wire 11 trained over a breast roll 12, table rolls 13,suction box 14, a couch roll 15, a turning roll 16, and return rolls 17.Stock is deposited on the upper wire run 11a from a head box 18 in theregion of the breast roll 12, and the stock is dewatered during itstravel on the upper wire run 11a to form a web W which is removed fromthe wire 11 by a pickup felt 19 urged against the web W by a suctionpickup roll 20. A rotary belt 21 mounted on support means 22 and 23 inaccordance with the principles of this invention is interposed betweenthe suction box 14 and the wire run 11a and may be guided during itstravel by a roll 24 or by ribs or rails associated with the supportmeans 22 and 23.

The present invention is directed to the lubricated support means 22 and23 in association with a moving belt and suction box in aiFourdriniertype paper machine as shown in Figure l. The structural details of thesuction box 14 and traveling belt 21 shown in the drawings form no partof this invention, and the illustrative suction box and movable belt areshown in some detail only to facilitate an understanding of the presentinvention. Accordingly, it will be appreciated that other suction boxesand movable belt may be substituted in lieu of the structures shown,although the illustrated constructions have proven in practice to havesubstantial advantages over the earlier arrangements. a

The suctionbox 14 is equipped with. a generally flat top 14a havingperforations 14b therein which open into the interior 14c. Exhaust meansin the form of a pump 25 (shown diagrammatically) connect to drop legs14d of the suction box 14 for the purpose of exhausting the interior14:: to eifect dewatering of the web W through the perforations 14b. Asappears inFigures 3 and 6, said perforations are countersunk at theirupper ends.

As is indicated in Figure 2, the perforations 14b in the suction box top14a are spaced longitudinally in the direction of wire travel. As shownin Figure 3, the perforations 14b in the suction box top or cover 14aare also spaced laterally and there are land areas Me on the generallyflat upper face of the cover 14a. Such land areas 14e are intermediatethe perforations 14b, and actually provide the supporting surface forthe cover 14a that supports the traveling belt 21 moving thereover. Itis to be further seen from Figure 3 that the land areas 14:; areprovided with shallow grooves 14f which face the belt 21 travelingthereover, the grooves being closed off from the interior 140 of thesuction-box 14. Further, as shown in Figure 6, relatively shallow,longitudinally spaced, and lateral extending grooves 14g communicatewith the grooves 14 to provide a substantial lubricated area wherebyresistance to belt movemen't'is reduced. As here shown, the land areasHe mounting the grooves 14], as well as the grooves themselves, extendlongitudinally of the direction of wire travel indicated by an arrow inFigure 2. The grooves 14 extend from near the ofi-running edge of thesuction box cover 14a to near the oncoming edge.

As indicated diagrammatically in Figure 3, means con nected to a sourceof liquid under pressure communicate with the grooves 14, and 14g forflowing liquid between the bottom side of the belt 21 and the suctionbox top 1411 to lubricate the same. Such means indicated generally at 26include a pump 27, a pressure control valve 28 (for maintaining apredetermined pressure in water header 29), and conduits 30 extendingfrom the header 29 to the grooves 14 As indicated by the arrows indashed lines in Figure 6, the water flows from the groove 141 along theland areas 14a and ultimately to the countersunk perforations 14b in thecover 14a. The flow indicated in Figure 6 is very slight and iscontrolled by the pressure of the belt 21 against the areas 14c,however, the flow is 'sufiicient 'to lubricate the rubber belt 21 and toprevent dragging thereof over the dry land areas Me. As is appreciated,other grooving arrangements may be employed.

The belt'21is provided with perforations or drainage holes 21a, .asindicated in Figure 3, and said holes are so mounted in the travelingbelt that. they do not align themselves with the grooves 14 in thesuction box cover 1411. In thisway water is not forced back up throughthe drainage holes 21a. Instead, the drainage holes 21a periodicallyalign themselves with the perforations 14b in the suction box cover 14a.The bottom side of the belt 21 has, of course. a'number of openingstherein formed by the drainage holes. 21a. Intermediate said drainageholes there are land areas 21b on the bottom side of the belt 21 whichcover the grooves 14 in the land areas 14c on the top side of thesuction box cover 14a. These belt land areas 21b are urged downwardlyagainst the suction box land areas 14s by the pressure differentialcreated by the suction box 14. For this reason, water is urged into thegrooves 14 under slight pressure to effect continuous seepage of waterbetween the faces of the land areas 148 and 21b, this seepage beingnecessary to prevent the rubber belt 21 from wiping the land areas 14::dry and thereby increasing the frictional drag. Preferably, theseepageof water is very slight so as not to overload the water removal systemfor the suction box 14.

The top side ofthe belt 21 is preferably provided with a plurality oflongitudinally spaced laterally extending grooves 01' channels 21c, oneof which is shown in Figure 3. Each such groove 21c is provided with oneor more drainage holes 21a, which as earlier noted perimeans 22 and 23which are the essence of the invention herein disclosed.

As appears in Figures 1 and 2, the belt support means 22 is located atthe oncoming side of the vacuum box 14, 7

while the belt support means 23 is positioned at the offrunning sidethereof. The support means 22 and 23 may be attached in any suitablemanner to fixed structure, and this may include a securement to thesuction box or to other machine structure. The lubricated belt supportdevices are essentially identical as to shape and construction to permitinterchangeability, and in view of their structural identity only one ofthe support means will be specifically herein described.

'Each supporting member or shoe 22 or 23 extends essentially entirelyacross the full width of the belt 21 to be in continuous contacttherewith prior to and after the belt moves along the suction box cover14a. Each lubricated shoe 'is'of generally arcuate shape and includes acurved main body portion 31 integral with a generally straight endportion '32 to provide an essentially fiat run for the belt prior topassage across the suction box 14. The supporting shoes 22 and 23 areconstructed of steel or the like, and in their preferred form areprovided with generally fiat inner and outer faces 33 and 34,respectively, which extend generally parallel to one another. The outerbelt contacting surface 34 is preferably smooth and polished to minimizefrictional losses.

Each shoe has an oncoming end 35 and off-running end 36, and it is to beseen that the end 35 of the shoe 22 is preferably curved as at 3511 toprevent belt damage. The end 36 of the shoe 22 abuts against theoncoming side of the suction box cover 14a, as shown best in Figure 2.Spaced circumferentially from the oncoming end 35 of each lubricatedshoe is a groove or open passage 3 extending transversely of the shoe.It is to be seen that the groove is formed along the contacting face 34of the shoe and is generally U-shaped in crosssection. The groove,however, preferably has a generally rouned bottom or base 38 and anoutwardly flared rounded discharge lip 39 "so that the lubricant canfiow uniformly out of the groove 37 over the lip 39 to provide alubricating film on the surface 34 contacting the inner face of the belt21. Experience has indicated that water performs efiectively as alubricant in the present instance.

Various arrangements may, of course, be utilized to supply water to thegroove '37 in the shoes 22 and 23, and one system comprises a pump 40(Figure 2) connecting with a water header 41 which is in turn suitablypassaged to communicate with a plurality of pipe lines or stems 42terminating at their opposite ends in the groove 37. In this mannerwater is directed to the transverse groove 37 at a plurality of spacedlocations along the length thereof. As is shown in Figures 4 and 5, theshoes 22 or 23 are bored as at 43 to receive the stems 42.

It may be desirable in certain applications to guide the belt 21 duringmovement along the shoes 22 and 23 and across the suction box cover 14a.The guide arrangement may take any one of several forms, includingarcuate ribs or rails on the shoes 22 and 23, suitable rails may beemployed at opposite ends of the suction box 14, or a single roll 24havinga flange 44 provided thereon may be utilized, as is shown inFigure 2. In other applications, on the other hand, the roll 24 maynotbe required since the supporting shoes or members 22 and 23 providethe necessary belt tension.

As earlier noted, it has previously been believed necessary to drive thebelt 21 over the suction box 14 by a pair of main rolls positionedat theoncoming .and 0E- running sides of-said'bbx. Howevenit'ha's been foundthat the belt 21 may be driven adequately by contact with theFourdrinier wire W, and accordingly, the external drive means employedin prior art arrangements can be eliminated. Of course, the waterpressure supplied to the vacuum box surface by the pump 25 of Figure 2must be sufficient to balance the vacuum forces and the weights of thebelt, wire and slurry deposited thereon. Accordingly, by elimination ofthe two main rolls which formed the loop of thebelt in the prior artstructures, the associated problems of imbalance and substantial costsof installation and operation are eliminated by the present invention.In this connection, it may be found that upon initial belt travel agreater water pressure will be necessary to the lubricated shoes 22 and23, however, during normal continuous operation when the belt isproperly tensioned the water pressure will be reduced.

In addition to the noted advantages of eliminating the out-of-balancecondition of the earlier used rolls, and the cost disadvantagesassociated therewith, the method of the present invention by the stepsof directing a continuous belt along a stationary arcuate path andlubricating the belt during said travel the further advantages ofreducing friction losses and belt wear are obtained. In addition, as isnow apparent, reduction of frictional losses and elimination of rollimbalance assures that the paper machine may be operated at maximumspeed and efliciency.

The sealing against the admission of air between the belt and thesuction box surface has the quite evident advantage of reducing thevacuum pump capacity required and the volume necessary to handleinasmuch as the water preferably used is not expansible. This featurehas the unobvious advantage of reducing the total load obtained at aparticular degree of vacuum since it re duces the area over which thevacuum operates to press the belt against the flat surface.

It will be understood that modifications and variations may be effectedwithout departing from the spirit and scope of the novel concepts of thepresent invention.

I claim as my invention:

1. In a paper machine which includes a suction box, a traveling wire andan endless perforated belt of generally the same width as the boxmovable by said wire over said box, the improvement which comprisesstationary support means forming the loop of the endless belt andextending essentially entirely across the width thereof, said supportmeans being passaged to provide a lubricating groove opening toward theendless belt, and means for supplying lubricant to said groove.

2. In a paper machine which includes a suction box, a traveling wire andan endless perforated belt of generally the same Width as the boxmovable by said wire over said box, the improvement which comprisesstationary support means of generally arcuate shape forming the loop ofthe endless belt and coextensive with the width thereof, the beltcontacting face of the support means being formed with a groovegenerally U-shaped in cross-section having a discharge lip flaredoutwardly in the direction of belt travel, and means for supplyinglubricant to said groove.

3. In a paper machine which includes a suction box, a traveling wire andan endless perforated belt of generally the same width as the boxmovable by said wire over said box, the improvement which comprisesstationary support means of generally arcuate shape forming the loop ofthe endless belt and coextensive with the width thereof, the beltcontacting face of the support means being formed adjacent the oncomingend thereof with a transverse groove of generally U-shape crosssectionhaving a mouth of relatively greater circumferential length than thebase to provide a discharge lip, and means for supplying lubricant tosaid groove.

4. In a paper machine which includes a suction box,

a traveling wire and an endless perforated belt of generally the samewidth' as the box movable by said wire over said box, the improvementwhich comprises a gen-' erally arcuate belt supporting member at boththe oncoming and off-running sides of the suction box and forming theloop of the belt, each of said members having a generally flat beltcontacting face provided therealong with a transversely extendinggenerally rounded lubricating groove, and means connecting with saidgroove at a plurality of spaced locations therealong to direct water tosaid groove and along the belt contacting face of the member tolubricate said belt.

5. In a paper machine which includes a suction box, a traveling wire andan endless perforated belt of gen erally the same width as the boxmovable by said wire over said box, the improvement which comprises ageneral-1y arcuate belt supporting member at-both the oncoming andofimunning sides of the suction boxand forming the loop of the belt,each of said members having a generally flat belt contacting faceprovided therealong with a transversely extending generally roundedlubricating groove, said groove having a mouth portion of relativelygreater circumferential length than the bottom thereof to provide adischarge lip outwardly flared in the direction of belt travel, andmeans connecting with said groove at a plurality of spaced locationstherealong to direct water to said groove and along the belt contactingface of the member to lubricate said belt.

6. In a paper machine which includes a suction box, a traveling wire andan endless perforated belt of gen erally the same width as the boxmovable by said wire over said box, the improvement which comprises agenerally arcuate belt supporting member at both the oncoming andoff-running sides of the suction box and forming the loop of the belt,each of said members having a generally flat belt contacting faceprovided therealong with a transversely extending generally roundedlubricating groove, said groove being spaced relatively more closely tothe oncoming end of the member than to the off-running end thereof andhaving a rounded discharge lip flared outwardly in the direction of belttravel to provide a uniform thickness lubricating film on the beltcoextensive with the witdh thereof, and means connecting with saidgroove at a plurality of spaced locations therealong to direct water tosaid groove and along the belt contacting face of the member tolubricate said belt.

7. Means for supporting an endless perforated belt traveling over asuction box in contact with a forming wire, said means comprising agenerally arcuate member extending generally entirely across the widthof the belt and said suction box, said member being provided on its beltcontacting face with a generally U-shaped cross-section lubricatinggroove provided with a discharge lip flared outwardly in the directionof belt travel to apply a generally uniform thickness lubricating filmbe tween the belt and contacting face of the member.

8. Means for supporting an endless perforated belt traveling over asuction box in contact with a forming wire, said means comprising agenerally arcuate member extending generally entirely across the widthof the belt and said suction box, said member being provided on its beltcontacting face with a transverse generally U-shaped cross-sectionlubricating groove having a rounded bottom and a rounded discharge lipflared outwardly inthe direction of belt travel to apply a lubricatingfilm of uniform thickness between the belt and contacting face of themember, the groove in said member being relatively closer to theoncoming end than the olfrunning end thereof.

9. In a paper machine which includes a suction box,

ing a generally; flat belt, contacting face provided therealong with atransversely extending: generally rounded lubricating groove; saidgroove having a mouth portion of; relatively greater: circumferentiallength than the bottom thereofto provide a discharge lip outwardly:

flared in the direction of belt travel, and means connecting with saidgroove at a plurality of spaced locations therealong to direct water tosaid groove and along the belt contacting face of the member tolubricate said belt,

10. In a paper machine which includes a; suction box, 15

a traveling wire and an endless perforated belt of generally the samewidth as the box movable by said wire over said box, the improvementwhich comprises. statthereof, said support means being" provided Withan,

opening for the supply of lubricant to the inner suliface" of said beltduring movement along said support means, and means for supplyinglubricant to said opening for application to the belt inner surface.

References Cited in the file of this patent UNITED STATES PATENTS EvansJune24, 1952 FOREIGN PATENTS Germany July 15, 1-899

